The closest prior art known to the inventor is disclosed in U.S. Pat. No. 4,624,386 issued Nov. 25, 1986 to the present inventor and another, and the references cited therein. Said patent discloses a tongue lanced from the can top except along a single transverse bend line and having a marginal edge disposed beneath an edge of the can top defining an opening therein, thereby preventing accidental displacement of the tongue upwardly through the opening in the can top. A thin film of synthetic resin material is adhesively secured to the underside of the can top in underlying relation to the tongue, so as to seal the opening shut until the tongue is intentionally bent upwardly through the opening by means of a ring tab to break the seal and provide access to the contents of the can.
One of the primary advantages of this earlier easy opening can top was the movement of the tongue upwardly and outwardly from the opening, thereby preventing contact between the tongue and the contents of the can. One of the disadvantages of this invention, however, was the need to apply additional force to lift the tongue over the overlapping edge of the opening, as compared to the relatively slighter force required to push the tongue downwardly through the opening, as accomplished with most conventional can top opening assemblies. U.S. Pat. No. 4,051,976 issued Oct. 4, 1977 to Perry discloses such a conventional opening assembly.
Thus, the present inventor was faced with the problems of devising a can top opening assembly which was economical and durable, that required no additional or auxiliary opening devices, that required less effort to open than previous models, and that prevented the tongue from having sustained contact, upon opening, with the beverage or other contents of the can.